It is our duty to keep our schoolyard clean and tidy.这句话是主语从句吗?It's one's duty是固定搭配吗?如何翻译,用法是什么?

it is our duty to do it is our duty to distribute to the society翻译 it is our duty to protect the environment. It is our duty to protect the environment It is our duty to ＿（study） hard. It is our duty to keep the classroom c--------. It.is.our.duty.to.try.our.best.to.dealIt.is.our.duty.to.try.our.best.to.deal.with.the.challenges.with.the.help.of.our.teachers. It's on duty to keep our classroom clean 改为同义句_______ ________ our classroom clean is our duty. We thought it our duty to take care of the orphans. 为什么不用“We thought it is our duty”呢? It is our duty to try our best during the time It is our duty to keep our e___ clean and tidy we think it our duty to help others为什么不加IS啊we think it is our duty to help others 翻译：It is our duty to try our best to deal with each challenge .It is our duty to try our best to deal with each challenge in our education with the help of our teacher. It is our duty to keep our classroom clean and tidy.中的It《our duty 》和 clean and tidy是什么成分 it is over duty to master it to,is,our,it,duty,protect,environment,the,连词成句 【NOISE 语法】It is our duty to protect them from being noisied.这里的noisied It is our duty to protect them from being noisied.【noisy 能用被动吗?】